Railway car spring



April 5, 1949. H. w. FROST, .n

.RAILWAY CAR SPRING Filed March 25, 1946 Big. 2

Big. 1

INVENTOR HAfi/FY w F2057 we.

ATTORN EY Patented Apr. 5, 1949 Harry W. Frost, Jr., Detroit, Mich., assignor to The Frost Railway Supply Co., Detroit, Mich., a

corporation of Michigan Application March 23, 1946, Serial No. 656,718

1 Claim. 1

My invention relates to friction springs of the coil type such as those used in conjunction with other coil springs, between the truck bolsters and the truck frames of railway cars, to serve as snubbing devices.

Friction springs of this type frequently comprise an inner, load-carrying coil and an outer coil or coils whose convolutions have frictional engagement with the convolutions of the inner coil, so that the convolutions of the outer coil will serve as snubbing elements during compression and expansion of the inner coil.

In springs of this type, it has been common practice to forge the end turns of the inner coil to tapered form, so as to provide an approximately flat seating surface, and also to form stop shoulders on such tapered sections, in position to be engaged by the extremities of the friction coils, to thus prevent too great creeping of the outer coils and to cause such turns or convolutions of these coils to be snapped back to their normal positions upon release of load from the inner coil. However, this arrangement reduces the strength of the inner coil, in its end turns.

My invention has for one of its objects the provision of a friction spring structure of such form that the inner coil can be formed of a bar that is of uniform cross-section throughout its length, with no necessity for stop shoulders thereon, and with its convolutions of uniform spacing; whereby the stresses on such coil will be more uniform, with more uniform tempering of the coil when quenching it, and avoidance of weak points that result from the usual taper forging and the forging of ,stop shoulders.

Another object of my invention is the provision of larger stop shoulders for the ends of the outer coils, to reduce danger of their ends jumping or crowding past the stop shoulders.

Still another object of my invention is to provide a coil spring structure wherein the coil is protected from excessively hard blows or load thrusts that would tend to deform or break it.

Figure l is a view partly in elevation and partly in section, showing a friction coil spring with my invention embodied therein; Fig. 2 is a plan view thereof; Fig. 3 is a plan view of the lowermost spring seat of Fig. 1; Fig. 4 is a vertical sectional view thereof, and Fig. 5 is a side elevational view thereof, taken from the side opposite to that shown in Fig. 1.

Only so much of a spring structure is shown herein as is necessary to an understanding of my invention, it being understood that the coil structure shown in the drawing will usually be employed in conjunction with other coils at each truck frame, as is common practice. The inner, load-carrying coil is shown at 6 and is preferably formed of bar stock, that is of uniform cross-sectional area throughout its length, and there is preferably uniform distances between its convolutions and hence there will be uniformity of stresses. The outer coil 1 will usually be made in two or more sections each of which has one and one-half or more convolutions and has angular friction surfaces cooperating at 8 with the friction surfaces on the inner coil.

Spring caps 9 and II] are provided for the ends of the coil 6, to serve as seats therefor. These seats are of identical form and a description of one will suffice for both. The caps have annular flanges, such as the flange II on the seat In, that respectively engage with a truck frame member at I2 and a bolster at I3. The flange II has an inclined or spiral surface I4 upon which the endmost convolution of the coil 6 will be fully seated when the coil is fully compressed under load. The uppermost convolution will engage the cap 9 in like manner.

A stop shoulder I5 extends from the low point to a high point of the surface I4 and, in addition, there is a protuberance I6 that constitutes an extension of the shoulder I5. The extremity of the coil 6 may abut the shoulder I5, and the coil 1 also engages the shoulder and the protuberance I6 when it tends to creep. The protuberance I6 reduces danger of the end of the coil I jumping past the stop shoulder.

Each of the caps 9-!!! has a cup-like depression and a squared opening I8 through which a square bar I9 extends. The caps are thus held against relative rotative movements by the spring thrust. In assembling the spring parts, before placing them in the car truck a cotter pin 20 is inserted through the hole in one end of the bar I9 and the bar inserted into the square openings in the pring caps and through the coil 6, Thereupon the coil 6 is compressed by pressure applied to the seats until the other end of the bar protrudes beyond the cup-shaped cap. Thereupon, a pin is inserted through the other end of the bar and the friction spring unit is ready for installation.

The bar I 9 is of such length that when the coil 6 is compressed to approximately the point at which its turns come solid with one another, the ends of the bar will become engaged with the members I2 and I3, to receive the thrust and thereby relieve the coil 6 of overload.

I claim as my invention:

Friction spring structure comprising a helical 3 load-carrying coil, a helical friction coil whose convolutions have frictional engagement with the convolutions of the other coil, a spring cap for each end of the load-carrying coil and each having .a seating surface sloped to conform to the angularity of the adjacent endmost convolution of the load-carrying coil when compressed, and each cupped inwardly into the load-carrying coil, stop shoulders on the spring caps, in position to be engaged by the extremities of the rods that form the coils, a tie bar of generally rectangular form in cross section extending along the axis of the spring coils and through complementally shaped holes in the cupped bottoms of the spring caps, to thereby hold the caps against relative rotation under thrusts by the coil ends, and retaining elements on the ends of the bar, for limiting expansive movements of the coils, the over- 4 all length of the bar being greater than the axial length of the spring and its caps, when the coils are fully compressed, to thereby receive impacts when the spring is at a nearly fully compressed 5 condition.

HARRY W. FROST, JR.

REFERENCES CITED The following references are of record in the m file of this patent:

UNITED STATES PATENTS Number Name Date 

